Can Robotic-assisted Surgery Improve the Outcomes of Revisional Metabolic and Bariatric Procedures?

| August 14, 2023

by Maher El Chaar, MD, FACS, FASMBS, and Wayne B. Bauerle, MD

Dr. El Chaar is with the Department of Surgery, Division of Bariatric Surgery, St. Luke’s University Hospital and Health Network in Allentown, Pennsylvania. Dr. Bauerle is with the Department of Surgery, St. Luke’s University Health Network in Bethlehem, Pennsylvania.

Funding: No funding was provided for this article.

Disclosures: Dr. El Chaar is a consultant for Intuitive Surgical. Dr. Bauerle has no conflicts of interest relevant to the contents of this article. 

Correspondence: Maher El Chaar, MD, FACS, FASMBS; email: [email protected]

Bariatric Times. 2023;20(7–8). Published online August 14, 2023.

At the beginning of the 21st century, the rate of obesity in the United States (US) was approximately 30.5 percent; that number has increased dramatically over time. In 2017, 42.4 percent of the US population had obesity, and 9.2 percent had severe obesity, a rise of almost five percent since the year 2000.1 Metabolic and bariatric surgery (MBS) has been shown to be the most effective and sustainable treatment option for patients with obesity and obesity-related metabolic conditions. Recently, we witnessed a significant increase in the overall number of metabolic and bariatric procedures. There was an increase of 10.8 percent between 2017 and 2018 and an overall increase of almost 60 percent since 2011.2 With the increased number of patients undergoing bariatric surgery, we are also witnessing an increased number of patients requiring revisional surgery due to weight recurrence or long-term complications. According to the most recent American Society for Metabolic and Bariatric Surgery (ASMBS) estimates, 15.4 percent of bariatric procedures performed in 2018 were revisional procedures, a striking 311-percent increase since 2011.2 Estimates for the year 2019 from available data, including Bariatric Outcomes Longitudinal Database (BOLD), the American College of Surgeons (ACS), and Nationwide Inpatient Sample (NIS), put this number at 16.7 percent (42,881 cases out of a total of 256,000 cases).3

Revisional cases are technically challenging and are associated with increased complication rates. Based on the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) data from 2015, it has been reported that the rate of complications following revisional stapling procedures was twice as high, compared to primary procedures.4 In a systematic review, the ASMBS also reported that reoperative bariatric surgery is associated with increased postoperative complication rates.5 Compared to primary Roux-en-Y gastric bypass (RYGB), revisional bariatric cases are associated with significantly greater intraoperative blood loss, prolonged operative times, higher likelihood for intensive care unit (ICU) admission, and prolonged hospital stay; revisional bariatric procedures also have higher rates of 30-day reoperations and less weight loss in comparison to primary RYGB.6

In a systematic review on reoperative bariatric surgery, members of the ASMBS Revision Task Force concluded that “morbid obesity is a chronic disease and acceptable long-term management after a primary bariatric procedure should include the surgical options of conversion, correction, or other adjuvant therapy to achieve an acceptable treatment effect in cases of weight recidivism, inadequate weight loss, inadequate comorbidity reduction, or complications from the primary procedure.”5 Dr. Henry Buchwald once said, “revisional surgery is a moral obligation.”7 According to the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) guidelines on revisional bariatric surgery (RBS), “Laparoscopic revisional procedures may be performed safely, but with more complications than primary bariatric procedures; therefore, the relative risks and benefits of laparoscopy should be considered on a case-by-case basis.”8 Given the increased number of revisional procedures and the increased complication rates associated with these procedures, it is only natural to explore new and innovative venues to improve patient outcomes and address the technical challenges associated with revisional procedures.

Robotic surgery has recently made its debut in the field of MBS with the introduction of new stapling devices, new energy devices, and a new surgical platform. Advantages of robotic surgery include added dexterity through wristed instruments, improved ergonomics, three-dimensional visualization, addition of a third arm, and stapling technology powered by computer algorithms. Studies have shown, using various scales, that robotic-assisted surgery can be “advantageous over laparoscopy” from the surgeon’s perspective when performing complex surgical tasks.9 Some authors even suggest that the use of a robotic-assisted approach in revisional procedures can lead to outcomes that are comparable to primary procedures.10 In a recent study reviewing the current trends in robotic utilization based on currently available MBSAQIP data for the years 2015 to 2020, our group found a trend toward increased national utilization of a robotic approach in MBS.11 According to our study, the greatest annual increase was found among robotic RBS (R-RBS; 3.70-fold difference, slope 2.4% per year) and sleeve gastrectomy (R-SG; 2.87-fold difference, slope 2.2% per year).11 However, the use of robotic surgery remains controversial because of cost concerns and lack of Level I evidence establishing its superiority over standard laparoscopic techniques. In a different study, we aimed to look at the outcomes of RBS performed robotically compared to the standard laparoscopic approach.12 The outcomes of R-RBS were compared to laparoscopic RBS (L-RBS) using the 2015 to 2017 MBSAQIP database. We selected all RBS and matched R-RBS to L-RBS using a propensity score matching system. Primary outcomes included 30-day serious adverse events (SAEs), 30-day organ space infections (OSIs), 30-day reoperations, and 30-day interventions. Based upon the results of our study, the incidence of 30-day SAEs, 30-day OSIs, 30-day reoperations, and 30-day interventions was lower for R-RBS (6.4%, 0.9%, 2.7%, and 2.3%, respectively), compared to L-RBS (7.7%, 1.4%, 3.6%, and 3.6%, respectively). However, these differences were not statistically significant. When comparing the 30-day readmission rate between R-RBS and L-RBS, the admission rate was higher in the R-RBS group (9.1% vs 6.4%, respectively).12 Utilizing a similar study design, we further investigated the use of robotic-assisted surgery for revisional procedures at our academic institution, comparing outcomes of R-RBS and L-RBS in a retrospective manner.13 A total of 167 patients were included in the analysis. Fifty-two patients underwent R-RBS (31%), and 115 patients underwent L-RBS (69%). Thirty-day major and minor complication rates for R-RBS and L-RBS were 1.9 and 5.8 percent versus 5.2 and 5.2 percent, respectively. That difference, however, was not statistically significant (p>0.05). Also, there was no statistically significant difference in readmission rates (3.8% vs. 8.7%, respectively; p>0.05) or intraoperative blood loss (35.5mL vs. 37.4mL, respectively; p>0.05) between R-RBS and L-RBS. However, R-RBS resulted in a shorter length of stay when compared to L-RBS (40.2 hours vs. 62.6 hours, p<0.05).13 Similarly, Gray et al14 demonstrated that R-RBS was associated with a shorter hospital stay compared to laparoscopic procedures. They also demonstrated that R-RBS had a safety profile equivalent to L-RBS. Dreifuss et al15 reported their experience in performing R-RBS and found that R-RBS is safe, with major morbidity and mortality rates of 3.9 and 1.3 percent, respectively. However, they did not compare outcomes of R-RBS to those of laparoscopic revisional procedures.15

Conversely, several studies have shown that the outcomes of robotic revisional surgery are suboptimal compared to laparoscopic revisional surgery. Using the 2015 to 2017 MBSAQIP Participant User Files (PUFs), Nasser et al16 reported that robotic revisional surgery resulted in increased complication rates, compared to a laparoscopic approach for sleeve gastrectomy, but not for gastric bypass. Clapp et al17 showed that both robotic and laparoscopic revisional procedures are safe, and in terms of postoperative complications, there was no significant difference between the two groups. However, the robotic approach resulted in longer operative times and hospital stays.17 In a recent systematic review by Bertoni et al,18 there was no significant advantage found when performing robotic revisional surgery; however, they also reported that their analysis showed noninferior efficacy of the robotic approach, compared to the laparoscopic approach.

It is important to note that although the MBSAQIP accreditation process and the publication of PUFs has made bariatric outcome data more readily accessible to participating institutions, the statistical analyses conducted by different institutions have demonstrated conflicting results, despite utilizing the same database. Variations in statistical methodologies, patient selection, inclusion and exclusion criteria, and patient matching have most likely contributed to the conflicting results.19

We attempted to address the above issues in a more recent article that investigated the outcomes of robotic-assisted bariatric surgery in comparison to the respective laparoscopic cases, using standardized definitions provided by the MBSAQIP.20 In that study, we used two separate datasets and separated primary, or initial, procedures from nonprimary procedures, then divided nonprimary procedures into revisions and conversions. According to MBSAQIP definitions of procedure types, an initial procedure refers to a primary metabolic and bariatric procedure, a conversion refers to a metabolic and bariatric procedure that is being converted to another type of metabolic and bariatric procedure, and a revision is a change to a current metabolic and bariatric procedure for repair or improvement of the existing metabolic and bariatric anatomy.21 Conversions and revisions may be performed to maintain weight loss, aid in future weight loss, or address surgical complications. In previous publications, revisions and conversions were not analyzed separately and were collectively referred to as RBS. In our analysis, we elected to utilize a composite score referred to as serious event occurrence (SEO), as one of our primary outcomes. SEO is the same outcome measure used by the MBSAQIP as a risk-adjusted metric in the MBSAQIP semi-annual reports provided to accredited bariatric centers. Based on this standardized definition, our analysis showed that robotic-assisted revisions had a lower incidence of SEOs, compared to laparoscopic revisions, but the difference was not statistically significant (1.00% vs. 5.06%, respectively). Robotic-assisted conversions had a higher incidence of SEOs, compared to laparoscopic conversions, but, similarly, that difference was not statistically significant (4.03% vs 3.32%, respectively).20

As previously mentioned, cost is also a major concern, especially after the passing of the Affordable Care Act (ACA). An emphasis on achieving the triple aim developed by the Institute of Healthcare Improvement (IHI), with a focus on cost reduction, in addition to improving the patient care experience and population health, should be at the center of all healthcare initiatives, including the adoption of new technologies. Cost, however, is institution-specific and hard to analyze on a national level because of contractual differences among healthcare institutions. In addition, surgeon volume, surgical technique, and experience can affect efficiency, clinical outcomes, and healthcare costs. Therefore, surgeons need to evaluate the cost of robotic surgery at their own institutions before deciding whether to implement this new technology. At our own institution, we looked at cost of robotic procedures and were able to demonstrate that primary robotic bariatric procedures are cost-effective compared to standard laparoscopic procedures.22–24

Managing revisional patients requires a multidisciplinary approach and surgical expertise. Although we believe the robotic approach can potentially offer technical advantages to the operating surgeon and improve patient outcomes, one needs to keep in mind that, like every new technology, robotic surgery has a learning curve.25–27 It is highly recommended for surgeons to adopt the robotic approach in primary cases before performing more advanced and technically difficult revisional procedures.

Given the above, we believe that the use of robotic surgery could prove to be a very promising approach to revisional MBS, as it has the potential to improve outcomes and overcome the technical challenges associated with such difficult cases. As surgeons gain more experience and become more efficient with robotic-assisted surgery, costs will decline, which could result in a wider adoption of the technology in revisional procedures.


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  2. English WJ, DeMaria EJ, Hutter MM, et al. American Society for Metabolic and Bariatric Surgery 2018 estimate of metabolic and bariatric procedures performed in the United States. Surg Obes Relat Dis. 2020;16(4):457–463.
  3. American Society for Metabolic and Bariatric Surgery. Estimate of bariatric surgery numbers, 2011–2021. Published 2023. Accessed 11 Aug 2023.
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  5. Brethauer SA, Kothari S, Sudan R, et al. Systematic review on reoperative bariatric surgery American Society for Metabolic and Bariatric Surgery Revision Task Force. Surg Obes Relat Dis. 2014;10(5):952–972.
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  11. Bauerle WB, Mody P, Estep A, et al. Current trends in the utilization of a robotic approach in the field of bariatric surgery. Obes Surg. 2023;33(2):482–491.
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  13. King K, Galvez A, Stoltzfus J, et al. Robotic-assisted surgery results in a shorter hospital stay following revisional bariatric surgery. Obes Surg. 2021;31(2):634–639.
  14. Gray KD, Moore MD, Elmously A, et al. Perioperative outcomes of laparoscopic and robotic revisional bariatric surgery in a complex patient population. Obes Surg. 2018;28(7):1852–1859.
  15. Dreifuss NH, Mangano A, Hassan C, Masrur MA. Robotic revisional bariatric surgery: a high-volume center experience. Obes Surg. 2020;31(4):1656–1663.
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  19. Petrick AT, Rosenthal RJ, Wood GC. Understanding the causes of conflicting outcomes reported using the same cohorts from the MBASQIP PUF data registry. Surg Obes Relat Dis. 2021;17(9):e42–e45.
  20. Chaar ME, Petrick A, Clapp B, et al. Outcomes of robotic-assisted bariatric surgery compared to standard laparoscopic approach using a standardized definition: first look at the 2020 Metabolic and Bariatric Surgery Accreditation Quality Improvement Project (MBSAQIP) data. Obes Surg. 2023;33(7):2025–2039.
  21. American College of Surgeons. Participant Use Data File. Accessed 11 Aug 2023.
  22. King K, Galvez A, Stoltzfus J, et al. Cost analysis of robotic Roux-en-Y gastric bypass in a single academic center: how expensive is expensive? Obes Surg. 2020;30(12):4860–4866.
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  24. Salem JF, Bauerle WB, Arishi AA, et al. Direct medical costs of robotic sleeve gastrectomy compared to laparoscopic approach in a single academic center. J Robotic Surg. 2023;17(1):49–54.
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